As fulfillment centers continue to accommodate more items, mezzanine structures and multiple levels or floors have provided a flexible option to expand capacity without the need for an increased ground-level footprint. Robotic systems have also been useful in warehouse and fulfillment center operations. Among other tasks, robotic systems can be relied upon to assist with picking and placing items. As another example, items can be moved from place to place in a warehouse using robotic systems to automate package handling operations.